An ex-Foreign Office minister has said he doubts Britain negotiated with the right people in its attempts to free five men kidnapped in Iraq.
In a BBC interview, Kim Howells also said he had become "very frustrated" with the Iraqi government.
The men were captured at the Ministry of Finance in Baghdad in 2007, and the bodies of two were released in June.
The Foreign Office said it was working extensively with trusted Iraqi counterparts to free the remaining men.
The bodies of Jason Swindlehurst, from Lancashire, and Jason Creswell, from Glasgow, were released last month.
Mr Howells, now the chairman of the commons intelligence and security committee, made the comments in an interview with Radio 4's The Report programme.
He said the kidnap had clearly been an inside job, as it was a well planned operation involving around 40 men, who knew exactly where to find the men in a very large ministry.
Mr Howell, who held the post until late 2008, said it had been extremely hard to get any reliable information about the hostages during the time they had been held captive.
Much of the negotiation had been through what he described as "extremely dubious middlemen".
He said he was not sure that during the time he was in office the intermediaries the Foreign Office were talking to were credible.
"I'm not convinced that we were ever negotiating with the right people, that's doubtful.
"The only real proof of life that I saw were the videos and there were stories circulating that a suicide had taken place, there were deadlines that came and went," he said.
Mr Howells also expressed his frustration with the Iraqi government, saying ministers would hint they knew something about the kidnap case but then nothing would happen.
"We would hear stories that the kidnappers had influence with elements of the Iraqi government or there were ministers in the Iraqi government who knew roughly who was involved in this kidnap and they would talk and persuade people to release the hostages, none of this proved to be true," he said.
The Foreign Office said it could not go into detail on the case while hostages were still being held.
But a spokesman said it it was working intensively for the release of the remaining hostages in a highly complex case, and it has excellent co-operation with trusted Iraqi counterparts.
The five captured men were an IT consultant, Peter Moore, and four security guards who were protecting him.
This is Britain's longest running hostage crisis since the days of Terry Waite and John McCarthy in Lebanon in the 1980s.
The British government has a policy of not making substantive concessions to kidnappers to discourage further kidnapping.
Find out more from The Reporton BBC Radio 4, Thursday 16 July at 2000 BST. You can also listen via the BBC iPlayerafter broadcast or download the podcast.
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